1. Field of the Invention
This invention relates to a cosmetic composition, particularly those containing at least one saponin or diacyl phosphatide in combination with monoacyl phosphatide.
2. Description of the Prior Art
There has recently been much research on emulsification and solubilization. As a result, improvement is seen in emulsifiers and solubilizers as well as technology of emulsification and solubilization. Now, stable emulsions and solubilized materials are being used in many fields.
Most of those emulsifiers and solubllizers are nonionic surface active agents having polyoxyethylene chains, anionic surface active agents such as fatty acid soaps, cationic surface active agents and amphoteric surface active agents. However, emulsified cosmetics and solubilized clear cosmetics in which those synthetic surface active agents are used generally have the drawback that they often stimulate the to skin and hair.
Under the above circumstances, phosphatide, particularly monoacyl phosphatide, has drawn attention. Japanese Patent Application Laid-Open 112007/86 discloses clear cosmetic compositions in which monoacyl phosphatide is used as a solubilizer. Japanese Patent Application Laid-Open 171407/86 discloses emulsion cosmetic compositions in which monoacyl phosphatide is used as an emulsifier.
However, the previous clear cosmetic compositions and emulsion cosmetic compositions in which monoacyl phosphatide is used have a problem with storage stability, particularly in low and high temperature conditions. In addition, further improvement is needed in organoleptic properties, particularly continued smoothness, and appearance such as texture and clearness.
That is, when clear cosmetic compositions are stored at a low temperature (below 5.degree. C.) or high temperature (above 40.degree. C.), monoacyl phosphatide tends to precipitate or cause turbidity. When emulsion cosmetic compositions are stored at a low or high temperature, viscosity and appearance such as texture change disadvantageously.
Meanwhile, saponin is a compound in which a nonpolar group (saponigen) such as sterol or triterpene is bound to saccharide such as penrose, hexose or uronic acid. They are found broadly in various plants besides certain type of asteroids. More than one types of saponin often exists in a single plant. Saponin has been studied as a medicamental component in recent years, but only a few cosmetic compositions are known in which saponin is used. It is suggested to use a saponin component of licorice, i.e., glycyrrhizin, in a cosmetic composition from a viewpoint of its anti-inflammatory effect, anti-allergic effect, antigen antibody suppression effect and steroid hormonic effect (Fragrance Journal, Vol. 3, No. 4, 39-41, 1975, Japan). It is known that in a skin cosmetic containing an oil obtained from seed of Oenothera tetraptera Cav., an extract from seed of Helianthus annuus L., root of Bupleurum falcatum L. or rhizome of Sanguisorba officinalis L. is blended as a stabilizer to prevent acidification or oxydation of the oil, and the extract contains saponin (Japanese Patent Application Laid-Open 178908/86). A shampoo is known in which a main component is an aqueous extract from pericarp of Sapindus mukurosii. This is said to have practically sufficient foaming ability and detergency (Japanese Patent: Application Laid-Open 125510/77). A hair tonic containing an extract from crude drugs such as Chinese matrimony vine is known in which polyoxyethylene-hardened castor oil, polyoxyethylene sorbitan sesquioleate or polyoxyethylene sorbitan monostearate is used as an emulsifier or solubilizer (Japanese Patent Publication 40923/83).
Meanwhile, diacyl phosphatide has been used as a wetting agent or emulsifier in the fields of foodstuffs, pharmaceuticals, cosmetics and the like, because it has a highly lipophilic fairy acid on its one end and a highly hydrophilic choline structure on another end and is, therefore, amphipathic. However, its emulsifying ability is not sufficient for some oily substances and, therefore, a prepared oil-in-water emulsion may cause phase inversion into a water-in-oil emulsion around room temperature or may have poor appearance or poor emulsion properties.
U.S. Pat. No. 3,652,397 discloses a process for the preparation of a lisophosphatide emulsifying agent by partially hydrolysing phosphatide obtained from soyabean, etc. This emulsifying agent contains unreacted phosphatide, i.e. diacyl phosphatide, besides the reaction product lysophosphatide, i.e. monoacyl phosphatide. The above U.S. Pat. No. 3,652,397 discloses the application of the lysophosphatide emulsifying agent mostly in foodstuffs such as margarine and mayonnaise. Except for just one line, "cosmetic preparations, for example lotions and salves", there is no concrete disclosure on cosmetic compositions. In reality, clear lotions cannot be obtained by the use of diacyl phosphatide. The U.S. Patent does not suggest that emulsion cosmetic compositions in which a combination of monoacyl phosphatide and diacyl phosphatide is used, show unexpectedly high stability during storage, improved organoleptic properties and appearance.